District authorities on Monday pleaded for people to come forward with tips in the unsolved shooting death of 10-year-old Makiyah Wilson, who was killed in a fusillade of 70 bullets on her way to an ice cream truck parked near her home.

D.C. Police Chief Peter ­Newsham said detectives have received a “substantial amount” of information from the public but not enough to arrest any of four masked gunmen — one armed with an assault-style weapon — who jumped from a stolen black Infiniti and sprayed the Clay Terrace courtyard with gunfire.

The shooting on July 16 in the 300 block of 53rd Street NE occurred at 8 p.m. as residents milled about the apartment complex and after Makiyah returned from swimming with her sister. She was shot as she stepped out of her front door clutching a $5 bill her mother had given her to purchase the treat. Several other people were wounded.

Police have not determined a motive, but Newsham said one theory is a dispute between neighborhoods. Police also have not said whether the gunmen, or a fifth person who was driving, targeted anyone in particular. Officials announced on Monday that the FBI has contributed $20,000 to the reward the city offers for a tip leading to an arrest and conviction, bringing the total to $45,000. Police recovered the vehicle used in the attack in Temple Hills, Md., three days later.

Mayor Muriel E. Bowser (D) said that residents of Clay Terrace, “like in many communities, have had enough of senseless violence and the use of illegal guns destroying families. We have to solve this homicide and solve it just as quickly as possible.”

The mayor noted that Makiyah “was doing what 10-year-olds do, near her home, when she was shot and killed.”

While violent crime is down 7 percent in the District, homicides are up 37 percent, from 67 recorded at this time last year to 92 so far in 2018. Newsham said authorities are “very concerned” about those numbers, and he blamed illegal guns. He said police have seized more than 1,000 of them so far this year.

On Friday, police said the department’s Gun Recovery Unit and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives arrested a man-and-woman team who police said bought a cache of firearms at a Northern Virginia gun show and took them to Southeast Washington. Newsham said a car stop revealed two of the guns in a vehicle and police found an additional five while searching a suspect’s home in the Washington Highlands neighborhood.

Court documents say the woman had earlier purchased two dozen weapons at the gun show since June 24. Isaiah Green, 27, and Jazmin Wilburn, 28, both of Southeast, were charged with several firearms violations.

The chief said he is nearly certain that the guns at Clay Terrace were illegal and used to “indiscriminately fire over 70 rounds in multiple directions. When the dust settled, Makiyah was left dead.”

Newsham said he thinks the investigation is “progressing in a very positive way” and that he hoped the gunmen would surrender.

Asked to quantify the number of tips, the chief said “a lot,” and he also indicated that many people are talking to detectives. “The folks I saw attending her funeral,” Newsham said, “are putting a lot of pressure on people to come forward with information.”